A depth map is an image that includes information about distances from a viewpoint to surfaces of objects (e.g., buildings and other structures). The depth map (e.g., a three-dimensional (3D) point cloud) may be acquired using a 3D optical distancing system. For example, a light detection and ranging (LIDAR) system may use one or more lasers or cameras to collect data points representing distances to different points on an area of interest (e.g., an area outside or inside a building) to generate the 3D point cloud.
A two-dimensional (2D) image may be generated by, for example, a camera, from the same viewpoint as the 3D point cloud and may be used to colorize the 3D point cloud. The generated 2D image and the 3D point cloud may be overlaid and processed to form a colorized 3D point cloud having color pixels attributed to the x, y, and z coordinates for the 3D point cloud.
Depth readings for surfaces of objects or structures including a transparent material such as, for example, glass may be at least partly inaccurate when a LIDAR system is used to generate the 3D point cloud. The light emitted by the LIDAR system is transmitted through the transparent material, and the depth reading corresponds to an object behind the transparent material, or no depth reading is received at all. Accordingly, the LIDAR system inaccurately determines distances from the viewpoint to transparent surfaces such as, for example, windows on a building.